• Management Science and Financial Engineering
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• v.15 no.1
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• pp.51-69
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• 2009

A network model and a Genetic Algorithm (GA) is proposed to solve the simultaneous estimation of the trip distribution and traffic assignment from traffic counts in the congested networks in a logit-based Stochastic User Equilibrium (SUE). The model is formulated as a problem of minimizing a non-linear objective function with the linear constraints. In the model, the flow-conservation constraints are utilized to restrict the solution space and to force the link flows become consistent to the traffic counts. The objective of the model is to minimize the discrepancies between two sets of link flows. One is the set of link flows satisfying the constraints of flow-conservation, trip production from origin, trip attraction to destination and traffic counts at observed links. The other is the set of link flows those are estimated through the trip distribution and traffic assignment using the path flow estimator in the logit-based SUE. In the proposed GA, a chromosome is defined as a real vector representing a set of Origin-Destination Matrix (ODM), link flows and route-choice dispersion coefficient. Each chromosome is evaluated by the corresponding discrepancies. The population of the chromosome is evolved by the concurrent simplex crossover and random mutation. To maintain the feasibility of solutions, a bounded vector shipment technique is used during the crossover and mutation.

• International Journal of Precision Engineering and Manufacturing
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• v.6 no.2
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• pp.50-54
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• 2005

We report a simple, low cost, and reliable method for assembling a multi-walled nanotube (MWNT) to the end of a metal coated scanning probe microscopy (SPM) tip. By dropping the MWNT solution and applying an electric field between an SPM tip and an electrode, MWNTs which were dispersed into a dielectric solution were directly assembled onto the apex of the SPM tip due to the attraction by the dielectrophoretic force. The effective measurement of a MWNT -attached SPM tip was demonstrated by direct comparison with AFM images of a standard sample with a bare AFM tip.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.29 no.4
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• pp.45-52
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• 1997

This study was carried out to investigate the adsorption characteristics of cationic starches onto BKP, BCTMP and talc. Concentration of the unadsorbed cationic starch contained in the supernatant of the pulp or talc slurries was determined using a spectoscopy method and the adsorption isotherm of cationc starch was constructed. When the equilibrium concentration of the cationic starch was low, almost complete adsorption of the starch onto BKP and BCTMP was observed. This indicates that electrostatic attraction is the main driving force for the adsorption of cationc starches onto pulps. BCTMP adsorbed greater amount of cationic starches than BKP since it contained more anionc functional groups on its surface. The adsorption amount of the cationic starch increased as the cationicity of the starches decreased. Surface charge density of the pulp and starch adsorption increased as the pH of the pulp slurry increased. Adsorption amount of the cationic starch onto talc was lower than that onto the pulp due to its low charge density and hydrophobic surface property.

• Journal of ILASS-Korea
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• v.13 no.1
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• pp.34-41
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• 2008

Molecular dynamic simulations have been carried out to study the effect of the nano-structure substrate and its temperature on cluster laminating. The interaction between substrate molecules and liquid molecules was modeled in the molecular scale and simulated by the molecular dynamics method in order to understand behaviors of the liquid cluster on nano-structure substrate. In the present model, the Lennard-Jones potential is applied to mono-atomic molecules of argon as liquid and platinum as nano-structure substrate to perform simulations of molecular dynamics. The effect of wettability on a substrate was investigated for the various beta of Lennard-Jones potential. The behavior of the liquid cluster and nano-structure substrate depends on interface wettability and function of molecules force, such as attraction and repulsion, in the collision progress. Furthermore, nano-structure substrate temperature and beta of Lennard-Jones potential have effect on the accumulation ratio. These results of simulation will be the foundation of coating application technology for micro fabrication manufacturing.

• Nuclear Engineering and Technology
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• v.47 no.6
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• pp.662-668
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• 2015

A suspension of titanium nanoparticles (Ti NPs) in liquid sodium (Na) has been proposed as a method to mitigate the violent sodium-water reaction (SWR). The interparticle potential between Ti NPs in liquid Na may play a significant role in the agglomeration of NPs on the reaction surface and in the bulk liquid Na, since the potential contributes to a reduction in the long-term dispersion stability. For the effective control of the SWR with NPs, a physical understanding of the molecular dynamics of NPs in liquid Na is key. Therefore in this study, the nonretarded Van der Waals model and the solvation potential model are employed to analyze the interparticle potential. The ab initio calculation reveals that a strong repulsive force driven by the solvation potential exceeds the interparticle attraction and predicts the agglomeration energy required for two 10-nm Ti NPs to be $4{\times}10^{-17}J$. The collision theory suggests that Ti NPs can be effective suppressors of the SWR due to the high energy barrier that prevents significant agglomeration of Ti NPs in quiescent liquid Na.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2022-2024
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• 2005

Electrical double-layer capacitor (EDLC) is an electrochemical energy storage device in which electric charges only accumulated by a pure electrostatic attraction force are stored on the electrolyte-electrode interface in a form of double layer and separated by the electrolyte. The composite was prepared by mixing nanosize $TiO_2$ and activated carbon through a means of ultrasonic vibration in ethanol solution for 30 min in various mass ratios of $AC:TiO_2$ to form activated carbone-semiconducting oxide composites. Either 1.0 M $LiClO_4/EC-DEC$ or $Et_4NBF_4$/EC-DEC was used as the electrolyte. It was found that with modification of $TiO_2$, the specific capacitance of activated carbon measured at $1mA/cm^2$ was increased from 40 to 50 F/g. This method is unique in comparison the conventional method because it uses semiconducting TiO2 other than electrochemically active materials such as $RuO_2$. The increase in specific capacitance could be attributed to the decrease in electric polarization, caused by the introduction of $RuO_2$.

• Korean Chemical Engineering Research
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• v.62 no.3
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• pp.269-273
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• 2024

The normal stress of TiO₂ ER fluid under an electric field showed negative values due to the electrostatic attraction force in the normal direction between particles and the absolute value increased dramatically with electric field strengths. The normal yield stress exhibited E² dependence similar to the dynamic yield stress, indicating that normal stress can be utilized for evaluating the ER effect. Numerical simulation demonstrated good qualitative agreement with the experimental data and suggested that the decrease in the absolute value of normal stress with increasing shear rates was attributed to the rearrangement of particle configurations under shear.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.36-36
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• 2017

Out of twenty common protein amino acids, there are many kinds of non protein amino acids (NPAAs) that exist as secondary metabolites and exert ecological functions in plants. Mimosine (Mim), one of those NPAAs derived from L. leucocephala acts as an iron chelator and reversely block mammalian cell cycle at G1/S phases. Cysteine (Cys) is decisive for protein and glutathione that acts as an indispensable sulfur grantor for methionine and many other sulfur-containing secondary products. Cys biosynthesis includes consecutive two steps using two enzymes-serine acetyl transferase (SAT) and O-acetylserine (thiol)lyase (OASTL) and appeared in plant cytosol, chloroplast, and mitochondria. In the first step, the acetylation of the ${\beta}$-hydroxyl of L-serine by acetyl-CoA in the existence of SAT and finally, OASTL triggers ${\alpha}$, ${\beta}$-elimination of acetate from OAS and bind $H_2S$ to catalyze the synthesis of Cys. Mimosine synthase, one of the isozymes of the OASTLs, is able to synthesize Mim with 3-hydroxy-4-pyridone (3H4P) instead of $H_2S$ for Cys in the last step. Thus, the aim of this study was to clone and characterize the cytosolic (Cy) OASTL gene from L. leucocephala, express the recombinant OASTL in Escherichia coli, purify it, do enzyme kinetic analysis, perform docking dynamics simulation analysis between the receptor and the ligands and compare its performance between Cys and Mim synthesis. Cy-OASTL was obtained through both directional degenerate primers corresponding to conserved amino acid region among plant Cys synthase family and the purified protein was 34.3KDa. After cleaving the GST-tag, Cy-OASTL was observed to form mimosine with 3H4P and OAS. The optimum Cys and Mim reaction pH and temperature were 7.5 and $40^{\circ}C$, and 8.0 and $35^{\circ}C$ respectively. Michaelis constant (Km) values of OAS from Cys were higher than the OAS from Mim. Inter fragment interaction energy (IFIE) of substrate OAS-Cy-OASTL complex model showed that Lys, Thr81, Thr77 and Gln150 demonstrated higher attraction force for Cys but 3H4P-mimosine synthase-OAS intermediate complex showed that Gly230, Tyr227, Ala231, Gly228 and Gly232 might provide higher attraction energy for the Mim. It may be concluded that Cy-OASTL demonstrates a dual role in biosynthesis both Cys and Mim and extending the knowledge on the biochemical regulatory mechanism of mimosine and cysteine.

• Journal of the Institute of Convergence Signal Processing
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• v.25 no.2
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• pp.77-85
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• 2024

The suspension device that connects the prosthetic leg and the residual limb allows lower limb amputees to wear prosthetic limbs, and is the most sensitive part when using prosthetic limbs as it is always in contact with the residual limb not only while walking but also in everyday life. In this paper, using the principles of attraction and repulsion of permanent magnets, we developed a magnetic lock suspension device that can fix the amputees and prosthetic legs of lower limb amputees by changing the polarity of the magnet. The operation method of the magnetic lock is that when neodymium magnets are placed on the left and right as NNSS based on a non-magnetic brass core, the magnetic force flows outward beyond the brass core using the adsorption member as a medium to generate bonding force. When rotated 90 degrees, the magnet moves to NSNS. The principle is that as the position moves, the magnetic force flows inward and cancels out.Based on this, we conducted a bonding test using tensile strength and a short-term comparative evaluation of the prosthesis with the shuttle lock suspension system, which was a comparison group, to verify reliability and evaluate satisfaction with the prototype. As a result, the tensile strength exceeding the appropriate bonding strength was confirmed, and the magnetic lock showed higher satisfaction than the shuttle lock. In the future, we plan to conduct long-term ADL clinical trials for commercialization and develop a product that can be distributed to actual amputees.

• The Journal of Engineering Geology
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• v.19 no.3
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• pp.345-350
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• 2009

The endpoint of the Yangbuk tunnel constructed at the national road between Gyeongju and Gampo is composed of massive cutting because the road is driven through the sides of mountain. PAP(Prestressed Anchor and PC Pannel) retaining wall as a slope stability method was established over this section. Part of the anchor in PAP wall became broken after six months. We performed inverse analysis through its measurements obtained until that time. An geological investigation to confirm the condition of ground layering and the attraction force test to find as to whether some errors might be present in the anchor were made. According to the back analysis, it was turned out that the value with soil parameter 90% that was applied to the original design was pertinent. In the redesign, the permissible stress in the anchor body was changed from 306 kN to 591 kN and 784 kN and the fixation position was increased from 11.0 m to 23.0 m. Nevertheless, five months have passed since the exchange of the anchor, the measurement results validate that stable state has been maintained. This research is considered a case that the immediate maintenance helps prevent the slope accidents.